Why can a breakpoint occur when returning TRUE from my OnCopyData?

Question

I am using Visual Studio to debug an ATL application.

When I step through return TRUEin this code, an error occurs:

BOOL CMainFrame::OnCopyData(CWnd* pWnd, COPYDATASTRUCT* pCopyDataStruct) {

    // Code snipped from here - maybe this causes stack/heap corruption?

    // I have a breakpoint here, if I step over (F10), AFX trace message 
    // is shown (as below)
    return TRUE;

}

This is a message box that is shown:

Windows called a breakpoint in foobar.exe.

This may be due to a bunch of corruption, which indicates an error in foobar.exe or any of the dlls loaded.

It may also be due to the user pressing F12 while calling phonejournal.exe has focus.

The output window may contain more diagnostic information.

The message is a bit vague, and I wonder what tools I can use to get more information. The debugger terminates the call AtlTraceVUin atltrace.h:

 inline void __cdecl CTrace::TraceV(const char *pszFileName, int nLine,
  DWORD_PTR dwCategory, UINT nLevel, LPCWSTR pszFmt, va_list args) const
 {
  AtlTraceVU(m_dwModule, pszFileName, nLine, dwCategory, nLevel, pszFmt, args);
 }

Answer 1

Microsoft Application Verifier . , . , , .

:

char *pc = malloc( 4 );
memcpy( pc, "abcdabcd", 9 );
free( pc );

, . (0x80000003). Verifier (, 0x1e9eff8). memcpy , memcpy. , free, , . .

Answer 2

(, ) - .